Handle :// as URL pattern

doc/changelog.asciidoc

@@ -65,6 +65,7 @@ Fixed
   Note it still does not work on Qt 5.10 (due to a Qt bug) and Qt < 5.9.2.
 - Repeated escaping of entries in `qute://log` when refreshing page.
 - The host blocker doesn't block 0.0.0.0 anymore.
+- Crash when using :// as URL pattern
 
 v1.4.1
 ------

qutebrowser/utils/urlmatch.py

@@ -142,7 +142,9 @@ class UrlPattern:
         Deviation from Chromium:
         - We assume * when no scheme has been given.
         """
-        assert parsed.scheme, parsed
+        if not parsed.scheme:
+            raise ParseError("Missing scheme")
+
         if parsed.scheme == 'any':
             self._scheme = None
             return

tests/unit/utils/test_urlmatch.py

@@ -96,7 +96,7 @@ from qutebrowser.utils import urlmatch
     ("http://[fc2e:bb88:edac]", 'Invalid IPv6 address; source was "fc2e:bb88:edac"; host = ""'),
     ("http://[fc2e:bb88:edac::z]", 'Invalid IPv6 address; source was "fc2e:bb88:edac::z"; host = ""'),
     ("http://[fc2e:bb88:edac::2]:2a2", "Invalid port: invalid literal for int() with base 10: '2a2'"),
-
+    ("://", "Missing scheme"),
 ])
 def test_invalid_patterns(pattern, error):
     with pytest.raises(urlmatch.ParseError, match=re.escape(error)):